关键词: 枯草芽孢杆菌, 生物防治, 防病机理, 小麦赤霉病, 抗菌物质

Abstract: Two strains B4,B6 belonging to Bacillus subtilis with excellent potential as biocontrol agents were investigated for the mechanisms of control wheat scab (F. graminearum).The antagonistic substances have a strong inhibiting activity against germination of spore and growth of mycelia.The major antifungal components are fat and water dissoluble substances.There is a large amounts of antifungal protein in cultural broth.The molecular weight of major proteins is about 44.01 kD and 58.57 kD.The best condition for producing antagonistic substances is YSP medium,pH 7.0,28℃ and enough oxygen.With the increase of cultural time,antifungal substances increase gradually and reach the highest amount at 72 h (B6 stain) and 96 h (B4 strain).The antagonistic substances are stable at pH 6 and pH 7.

Key words: Bacillus subtilis, biocontrol, mechanisms of control wheat scab, wheat head blight, antifungal substances